Device for governing the pressure or quantity of a flowing gaseous medium



May 20, 1969 E. NORELIUS 3,444,894 DEVICE FOR GOVERNING THE PRESSURE OR QUANTITY OF 4 A FLOWING GASEOUS MEDIUM Filed Jan. 10, 1967 FIG}.

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BY EINAR NORELIJUS A YS.

United States Patent 3,444,894 DEVICE FOR GOVERNING THE PRESSURE 0R QUANTITY OF A FLOWING GASEOUS MEDIUM Einar Norelius, Jonkoping, Sweden, assignor to Aktiebolaget Svenska Flaktfabriken, Stockholm, Sweden Filed Jan. 10, 1967, Ser. No. 608,335 Claims priority, application Sweden, Jan. 13, 1966, 400/66 Int. Cl. F16k 3/22; F24f 13/10 US. Cl. 137-62528 4 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to a device for governing the pressure or quantity of a flowing gaseous medium for instance in ventilating and air-conditioning plants.

In the US. patent specification 3,139,106 is prior known a device for maintaining constant the static pressure in a conduit for a flowing gaseous medium.

The known device consists of a housing in which are arranged two damper blades movable towards each other and a central body arranged along the middle of the duct housing between the two damper blades so that these in their closed position will be in engagement with the side surfaces of the central body. By splitting the fluid flow into two parts of current by means of a central body the normal flow character of the fluid flow will be rapidly restored after a disturbance at the point of regulation. This will involve a low sound level and gives a great freedom of choice with respect to the location of the device in a plant.

Contrary to the known device the device in accordance with the present application is intended to work with a high degree of throttling, i.e., when the quantity of fluid flow passing through the device has been reduced to about 40% of the maximum value. This involves great velocities and great pressure drops for the flowing fluid. With a symmertical location of the central body in accordance with the known device a high noise level will be obtained at the throttling point owing to the occurring high velocities at this point. The noise is created by the mixing of the air currents after the central body. To eliminate the noise the velocity of the air must be decreased before the two branch currents are intermixed which can be carried out either by the extension of the central body or by turning same. An extension will result in a needless long device. By giving the device the shape disclosed in claim 1 the disturbing noise will be entirely eliminated. The turning is carried out along an axis located in the point of intersection for the curves which represent the movement of the damper blades. By way of example will now be described a device made in accordance with the invention and illustrated in the accompanying drawing figures wherein:

FIG. 1 shows a longitudinal section of a governing device in accordance with the invention, and

FIG. 2 shows the same device seen in front view.

In a duct housing 1 there are arranged two substantially are shaped damper blades 2 fastened to arms 3 being turnable around axles 4. The housing is fitted with pockets 5 into which the damper blades 2 can be introduced entirely or partly so that a passage 6 of variable cross-sectional flow area in the housing 1 is created. Between the damper blades and along the centre-line of said passage there is arranged a central body 7. The fluid flow through said passage will thus be divided into two currents. To eliminate a disturbing noise from the throttling point the central body 7 is turned around its turning axle so that it has an angle of about 10 to the main direction of the fluid flow. The turning of said body takes place around an axle 8 located in the middle of said passage and in the point of intersection between the two curves of the damper blades 2 during their movement. The form of the central body is adapted to that of the housing and the cross-section of the body has a shape adapted to aerodynamic viewpoints and is provided with a rounded front edge from which the central body is tapering backwards towards a pointed rear edge. The front and the rear edges are defined by the flow direction of the fluid through said flow passage.

What I claim is:

1. A device for governing the pressure or quantity of a flowing gaseous medium comprising a housing defining a longitudinal passage open at each end, two damper blades arranged in said housing and being movable towards each other in paths substantially perpendicular to the longitudinal axis of said passage, and a central body coextensive with and positioned between the two damper blades in said passage and extending from one side of the passage to the opposite side, said central body having a cross-sectional shape tapering from a rounded upstream end of substantial thickness to a pointed downstream end, the rounded upstream end of the central body being located at the intersection of the two paths of movement of said dam-per blades to be engaged thereby, said central body being positioned with its axis at an angle of about 10 with the longitudinal axis of said passage.

2. A device as claimed in claim. 1, including a shaft located transversely with respect to the flow direction along the center line of said flow passage at the line of intersection between the two paths of movement of said damper blades, said central body being turnable around said shaft.

3. A device as claimed in claim 1 wherein the central body is covered with a sound-absorbing material.

4. A device as claimed in claim 1 wherein each of said damper blades consists of a substantially arc-shaped blade and at least one arm mounting each blade and turnably pivotable to displace each damper blade towards the other along an arcuate path substantially perpendicularly to the longitudinal axis of said passage, said paths intersecting at the rounded upstream end of said body.

References Cited UNITED STATES PATENTS 1,437,423 12/1922 Jackson 251212 2,214,736 9/1940 Carmichael et a1. 137612 2,898,080 8/1959 Smith 251212 X 3,139,106 6/1964 Wallin 137375 FOREIGN PATENTS 50,950 1911 Austria.

ARNOLD ROSENTHAL, Primary Examiner.

US. Cl. X.R. 

